Batter&#39;s swing analyzing apparatus



Jan. 14, 1964 DE LA VERNE RAY ETAL 3,117,451

BATTER'S swme ANALYZING APPARATUS Filed Dec. 5, 1960 2 Sheets-Sheet 1200 VDC Fig. 5

IN V EN TORS. RAYMOND J. TANGUAY ROBERT F? LEWIS DELAVERNE RAY BUCKHORN,CHEATHAM BIBLORE ATTORNEYS United States Patent This invention relatesto a method of and apparatus for analyzing a batters swing.

A main object of the invention is to provide an apparatus for indicatingbat speed, plane of the bat swing, and point of impact of the bat withthe ball during the bat swing. With these three results, defects in thebatters swing can readily be determined, analyzed and corrected.

Another object of the invention is to provide an apparatus of the typeabove indicated for indicating any one of the conditions above named.

arious other objects will be apparent from the following descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view in diagrammatic form showing part of theapparatus of the invention and its relation to a bat, batters plate andthe strike zone;

FIG. 2 is a plan view of the arrangement disclosed in PEG.

FIG. 3 is a block diagram of a circuit which constitutes part of thepresent invention;

FIG. 4 is a fragmentary sectional view of a baseball bat showing part ofthe present invention; and

FIG. 5 is a circuit diagram of the photoelectric cell unit.

Referring to FiGS. l and 2, there is a home plate 11 and a batters box13 for a right-handed batter. A baseball bat is shown as being swungupwardly through a strike zone 17, the full lines indicating a firstposition and the dotted lines showing a subsequent position. FIG. 4shows that the end of the bat i5 is equipped with a reflector 19 forreflecting a beam of light directed at the end of the bat.

Referring now to FlG. l, a source 21 of infrared light is shown asdirecting a beam of light 23 toward the strike zone 17 so as to projectlight onto the end of the hat. The reflector 19 will reflect a spot oflight toward a vertical photoelectric cell unit 25 which includes aplurality of vertically arranged photoelectric cells 37 so connected, aswill be presently set forth, that the higher the cell, the greater theamplitude of the pulse produced by the cell.

As is evident from FIG. 2, the first light source 21 is disposed in aclockwise direction from the photoelectric cell unit 25 an angularextent of less than 90 and in fact an angular extent of a minor acuteangle. The distance of the first light source 21 and the photoelectriccell unit 25 from the batters plate is the san e. The photoelectric cellunit 25 has a second light source 39 for directing a beam or" light 41toward the strike zone. The light source 39 directs the beam in anupwardly inclined angle the same as does light source 21.

Referring to FIG. 2, assuming that the bat is in the full line positionin FIG. 2, the beam 23 from the source 21 will strike the reflector 19and be reflected onto the photoelectric cell unit 25. This creates afirst pulse of electrical energy. As shown in FIG. 1, it is assumed thatthe bat is pointed somewhat downwardly and occupies a low position andhence the beam 23 will strike a lower cell 37 to create a pulse ofelectrical energy having an amplitude less than if a higher cell werestruck.

Now returning to FIG. 2, as the bat assumes the dotted line position inFIG. 2, the light beam 41 will be reflected directly back to thephotoelectric cell unit to strike the unit. From FIG. 1, it is apparentthat the beam of light Patented Fan. i4, 1984 "Ice 2 41 is going tostrike the upper part of the photoelectric cell unit 25' and create asecond pulse of greater amplitude than that of the first pulse.

The box 25 also contains a microphone 5'1 which will generate a pulse ofelectrical energy when the bat strikes the ball.

For convenience hereinafter, the pulse of light created because of thelight source 21. will be referred to as pulse A, whereas the pulsecreated by the beam issuing from the source 39 will be referred to aspulse B, and the pulse created by the microphone 51 as pulse C.

Referring to FIG. 5, the circuit diagram of the photoelectric cell unitis disclosed fragmentarily and the circuitry is located in the unit 25.In a typical installation, there may be thirty cells of the constantcurrent type, that is, where the output current is a function of lightintensity only and independent of applied voltage. The cells aredesigned to have maximum response to infrared light.

Only five of the thirty cells are shown in FIG. 5 and labeled cell 30,29, 28, 27 and 1. The left-hand sides of the cells are connected to acommon conductor 99 and the right-hand sides of the cells are connectedto a common resistance line containing a resistor for each cell,resistances R39, R29, R28, R27, R2, R1 being shown. The resistance R1 isgrounded, and there is a supply conductor Hill, which in a typicalinstallation may be at 200 volts D.C.

The output conductor is numbered 161. It is apparent that the amplitudeof an output pulse at 101 will vary from a low value for a low cell to aprogressively higher value for progressively higher cells.

in a typical installation, the thirty cells may be arranged in avertical row commencing approximately one inch above the ground andextending to slightly more than eighty-three inches above the ground. Ifeach cell has a vertical dimension of approximately two and five-eighthsinches, it is apparent that there will be little space between cells.

With the above relationship, the output from the unit 25 Will varysubstantially linearly even though the light spot reflected from the batpasses between the cell centers. In fact, if the spot size is made tohave a diameter equal to the diameter of a cell plus the distance of thespace between cells, or a multiple of these combined dimensions, theoutput of the unit 25 will be linear.

Level Stroke Determination As the player swings at a ball, a spot oflight passes over the photoelectric cell unit 25 and generates the firstvoltage pulse, pulse A, of approximately 250 to 500 microsecondsduration and of an amplitude corresponding to how high on the cell groupthe spot passage occurred. This pulse is then amplified at 2 .92. tobring its amplitude between the measuring range of 10 to 50 volts. Next,the pulse passes through a gate driver 263a (cathode follower) and afirstpulse gate 204 to a pulse rectifier 2&5, where it is rectified andthe peak voltage of the pulse is stored on a capacitor.

From a deooupler 263i!) (cathode follower) a second use of this pulse(actually the timing part of the double pulse) is made by routing itthrough a squaring amplifier 21th (Schmitt-Trigger) where it is squaredinto a 100 volt pulse with short rise and fall times. This output isthen ditferentiated into sharp positive and negative pulses. These arethen fed to a speed control counter 215 in the form of an Eccles-Iordanbistable multivibnator in such a manner that the multivibrator respondsonly to the negative pulse which occurs at the end of pulse A. TheEccles-lordan speed counter control 215, in responding to this negativepulse reverses its condition and via con- .3 trol buifers 21s (cathodefollowers) turns the first pulse gate 204 oif and opens a second pulsegate 311 preparing it to accept pulse B from the photoelectric cell unit25.

Approximately 3,000 to 6,000 microseconds following pulse A, dependenton the speed of the bat, the angles involved between the bat and theinfrared sources and the photoelectric cell unit 25, a second light spotwill cross the photoelectric cell unit 25 and an output voltage pulse Bof 250 to 500 microseconds duration and an amplitude dependent on theheight of the light spot will be developed in the photoelectric cellgroup common output. Pulse B will follow the same path as pulse A, thatis through the amplifier 20-2 and the gate driver and deeoupler 203a and203b, but due to the switching action of the control multivibrator 215previously described, will now pass through the second pulse gate 311and thence to a pulse rectifier :and storage circuit 312. where it isrectified and stored in the same manner as pulse A.

The two stored voltages are then fed simultaneously to a companator 406where they are subtracted and a positive and a negative differencesignal appear in the output. If the two storage voltages are equal, nooutput results. if pulse A is larger than pulse B, the positivedifference output rises and the negative difference output falls. Wherepulse B is the greater, the positive difference output falls and thenegative difference output rises.

These signals then pass to a combiner-inverter 407 which is acombination of two tubes operating at a point approaching cutoff so thatthey only respond to rising signals on their grids. Thus, no matterwhich pulse exceeds the other, a unipolar error signal proportional tothe difference appears at the plates of the combinerinverter 4-07. Thiserror signal is then amplified in a differential DC. amplifier 408 andpasses to a decision relay keyer 409 (Schmitt-Trigger). If the errorsignal exceeds a predetermined potential, the decision relay will betriggered to condition a red light to goon. If not, it will condition agreen light to go on. If desired, the error may be fed to a meter togive an indication of the magnitude of the error.

As in the case of pulse A, pulse B from the phot electric cell unit 25also passes from the decoupler 203b through the squaring amplifier 2E0to the speed counter control 215 which once again reverses itscondition, returning to the initial state at the end of pulse B. Thisaction of the speed counter control, passing through the control buffers2.16 is fed to a readout control circuit 440 (bistable Eccles-iordanmultivibrator) and thence to a readout relay 441 (Schmitt-Trigger). Thereadout relay 441 now applies voltage to the decision hel-ay 409 causingthe appropriate light to light in accordance with the decision made asabove. Additional contacts onthe readout and decision relays lock thedecision keyer 409 for the readout period.

Speed of Stroke M'easzzrement As mentioned above, the speed countercontrol multi vibrator 215 was caused to flip by the trailing edge ofpulse A, and to flop by the trailing edge of pulse B. Thistimebetwecn-events signal is fed through the control buffers 216 tocontrol a count pulse gate 5l7. Pulse A causes this gate to open andfood 100 microsecond pulses (100 microseconds apart) from a kc.oscillator 52-5 (Wien bridge) and a squaring amplifier 526 (Schmitt-Trigger) into a five-stage binary counter chain 618. Pulse B causes thegate 517 to close, stopping the count. The condition of the variousstages in the binary chain will then indicate the number of 100microsecond intervals which elapsed between the two cell pulses A and B.

it will be noted that the maximum count of the counter chain is 32 or3,200 microseconds, while the interval of interest (time between butpositions) is 3,500 to 6,000 microseconds. Thus, the counter will cyclecompletely once before pulse B arrives and consequently take its counton the second cycle, so that 3,200 microseconds are absorbed in thefirst cycle and the measurement occurs between 3,200 and 6,400microseconds. A series of 2-to-1 ratioed resistors (notshown) feeds theconditions of the binary stages into a common readout buss thence via areadout amplifier 623 (cathode follower) to a meter 624, the meter beingcalibrated to directly convert the time measurements to equivalent milesper hour.

Circuitry for accomplishing the functions of the various blocks of FIG.3 is known to those skilled in the art. However, novel circuitry [isbeing devised for accomplishing the functions of certain of the blocks,for instance the comparator 406, and will be made the subject matter ofa subsequent application.

Circuitry for conversion of the digital information of the binarycounter 61% to an andog signal for the meter 624 is shown at page 214 ofDigital Counters and Computers by Bukste-in (Rinehart & Company).

Impact Timing It is assumed that the proper point of impact or" the ballwith the bat should occur at the instant that the bat reaches a lineperpendicular to the line of flight of the ball. It is apparent fromFIG. 2 that the second light source 3? is located so that its beam 41 isperpendicular to a line extending through the plate 11 and the pitchersmound (not shown). Thus when the bat reaches a position coinciding withthe beam 41 as the parts are shown in FIG. 2, the bat should, in anideal situation, strike the bell. By comparing pulse B with a pulseproduced by the sound of the impact, in respect to timing, an indicationof the actual point or" impact may be obtained.

Since the speed counter control 215 returns to normal with time trailingedge of pulse B, this action is used via the control buffers 216 toactivate a timing counter control 629 (EcclesJordan bistablemultivibrator) to on. This opens 'a count gate 630 allow-ing microsecondpulses to pass from the 10 kc. oscillator 525 and squaring amplifier 526to a six stage binary counter chain 631 and counting action starts.

The sound of the impact is picked up by the micro phone 41 and the pulseC thus created is suitably amplified at 727, squared at 728(Schmitt-Trigger) and used to trigger the timing counter control 629 tooff, to termihate the count. Since, the microphone 41 is locatedapproximately 12 feet from the actual point of impact, there is a delaywhile the sound travels through the air and this must be accounted for.This delay is of the order of 10,000 microseconds and thus while theimpact may occur before pulse B, the sound will arrive at the microphone41 after the light cell pulse has arrived at the count pulse gate 630.The counter chain is capable of 64 counts or total time of 6,400microseconds. The counter chain thus cycles one time before pulse Carrives and takes measurement in the second cycle. Thus the arc ofmeasurement is from 6,400 to 12,800 microseconds.

The binary chain readout is here accomplished identically with that inthe speed counter chain, a readout amplifier 737 (cathode follower) andan impact timing meter 738 being provided for the chain 631 to indicateproper impact or early or late impact and to what extent.

Reset For fully automatic operation, it is necessary that the machineaccomplish all functions and return itself tothe idle no readingcondition after one second or other predetermined time. To accomplishthis, pulse A is fed from the squaring amplifier 210 to an automaticreset timer circuit 814. This circuit is a one second durationmonostable multivibrator (Schmitt-Trigger) which pulse A triggers to theoff normal condition. Triggering to the oif normal has no effect on therest of the circuitry, but at the expiration of one second when thereset timer 814 returns to normal, its output is differentiated and fedvia a switch 333 to a reset amplifier 839 and then to both counterchains 613 and 631, to erase the counts, to the speed counter control215, to insure idle condition (in case there is no pulse B, forinstance) to the readout control 440 to terminate readout of the levelswing and unlock the level swing decision 4159, and to a comparator andstorage reset circuit 913 to discharge the pulse storage capacitors tozero.

In the manual condition of the reset switch $33 the reset timer 314 isdisconnected and the reset pulse manually generated by the operation ofthe switch.

F urzher Explanation It is contemplated that difierent batters mayassume different positions in the batters box, and while the unit 25 andthe lig t source 21 may be moved to accommodate this, or mounted ontracks for ready in unison adjustment, this will not be necessary inmost instances because the speed and the level stroke indications willbe unaffected and the point of impact indication will still bemeaningful. If desired, the meter 733 can have an adjustable zero orideal indicator and the person checking the batter can merely adjust theindicator according to the position of the batter.

For left-handed batters, a second unit 25 and source 21 may be provided,or the unit 25 and source 21 shifted to the other side of home plate.

Having described the invention in what is considered to be the preferredembodiment thereof, it is desired that it be understood that theinvention is not to be limited other than by the provisions of thefollowing claims.

We claim:

1. An apparatus for indicating bat speed, plane of bat swing, and pointof ball impact during the bat swing, comprising means including verticalphotoelectrical cell means to face a batters plate in spaced relationthereto, said photoelectric cell means creating a pulse of electricalenergy which varies in amplitude in accordance with the height of a beamof light crossing said means, light beam means responsive to the swingof a bat across the batters plate for projecting a first beam on saidphotoelectric cell means as the bat passes a first predetermined placeto create a first pulse of electrical energy, and for projecting asecond beam on said photoelectric cell means as said bat passes a secondpredetermined place to create a second pulse of electrical energy, saidlight beam means being arranged so that the first light beam strikessaid photoelectric cell means at a height proportional to the level ofsaid bat when said bat is at said first predetermined place, and so thatthe second light means strikes said photoelectric cell means at a heightproportional to the level of the bat when said bat is at said secondpredetermined place, whereby if the bat level is different at saidplaces, the amplitudes of said first and second pulses will bedifierent, means for comparing the amplitude of said first and secondpulses and indicating when the difference exceeds a predetermined value,means for indicating the difference in time between the two pulses toindicate the speed of the batters swing, means responsive to the impactof the bat with a ball to create a third pulse of electrical energy, andmeans for indicating the difference in time between the third pulse andone of the first two named pulses.

2. An apparatus for indicating the plane of swing of a bat comprisingmeans including vertical photoelectric cell means to face a battersplate in spaced relation thereto, said photoelectric cell means creatinga pulse of electrical energy which varies in amplitude in accordancewith the height of a beam of light crossing said means, light beam meansresponsive to the swing of a bat across the batters plate for projectinga first beam on said photo electric cell means as the bat passes a firstpredetermined place to create a first pulse of electrical energy, andfor projecting a second beam on said photoelectric cell means as saidbat passes a second predetermined place to create a second pulse ofelectrical energy, said light beam means being arranged so that thefirst light beam strikes said photoelectric cell means at a heightproportional to the level of the bat when said bat is at said firstpredetermined place, and so that the second light means strikes saidphotoelectric cell means at a height proportional to the level of thebat when said bat is at said second predetermined place, whereby if thebat level is different at said places, the amplitudes of said first andsecond pulses will be different, means for comparing the amplitude ofsaid first and second pulses and indicating when the difference exceedsa predetermined value.

3. An apparatus for indicating the plane of swing of a bat and bat speedcomprising means including vertical photoelectric cell means to face abatters plate in spaced relation thereto, said photoelectric cell meanscreating a pulse of electrical energy which varies in amplitude inaccordance with the height of a beam of light crossing said means, lightbeam means responsive to the swing of a bat across the batters place forprojecting a first beam on said photoelectric cell means as the batpasses a first predetermined place to create a first pulse of electricalenergy, and for projecting a second beam on said photoelectric cellmeans as said bat passes a second predetermined place to create a secondpulse of electrical energy, said light beam means being arranged so thatthe first light beam strikes said photoelectric cell means at a heightproportional to the level of the bat when said bat is at said firstpredetermined place, and so that the second light means strikes saidphotoelectric cell means at a height proportional to the level of thebat when said bat is at said second predetermined place, whereby if thebat level is different at said places, the amplitudes of said first andsecond pulses will be diiferent, means for comparing the amplitude ofsaid first and second pulses and indicating when the difierence exceedsa predetermined value, means for indicating the difference in timebetween the two pulses to indicate the speed of the batters swing.

4. An apparatus as in claim 1 in which said light beam means includesreflector means on the bat.

5. An apparatus as in claim 2 in which said light beam means includesreflector means on the bat.

6. An apparatus as in claim 3 in which said light beam means includesreflector means on the hat.

7. An apparatus for indicating bat speed, plane of bat swing, and pointof ball impact during the bat swing, comprising means to face a battersplate in spaced relation thereto and creating a pulse of electricalenergy which varies in amplitude in accordance with the height of a batand operative as the bat passes a first predetermined place to create afirst pulse of electrical energy and operative as said bat passes asecond predetermined place to create a second pulse of electricalenergy, whereby if the bat level is different at said places, theamplitudes of said first and second pulses will be different, means forcomparing the amplitude of said first and second pulses and indicatingwhen the difierence exceeds a predetermined value, means for indicatingthe diiference in time between the two pulses to indicate the speed ofthe batters swing, means responsive to the impact of the bat with a ballto create a third pulse of electrical energy, and means for indicatingthe difference in time between the third pulse and one of the first twonamed pulses.

References Cited in the file of this patent UNITED STATES PATENTS2,283,277 Modine May 19, 1942 2,571,974 Walker Oct. 16, 1951 2,784,001Simjian Mar. 5, 1957 2,825,569 Alvarez Mar. 4, 1958

7. AN APPARATUS FOR INDICATING BAT SPEED, PLANE OF BAT SWING, AND POINTOF BALL IMPACT DURING THE BAT SWING, COMPRISING MEANS TO FACE ABATTER''S PLATE IN SPACED RELATION THERETO AND CREATING A PULSE OFELECTRICAL ENERGY WHICH VARIES IN AMPLITUDE IN ACCORDANCE WITH THEHEIGHT OF A BAT AND OPERATIVE AS THE BAT PASSES A FIRST PREDETERMINEDPLACE TO CREATE A FIRST PULSE OF ELECTRICAL ENERGY AND OPERATIVE AS SAIDBAT PASSES A SECOND PREDETERMINED PLACE TO CREATE A SECOND PULSE OFELECTRICAL ENERGY, WHEREBY IF THE BAT LEVEL IS DIFFERENT AT SAID PLACES,THE AMPLITUDES OF SAID FIRST AND SECOND PULSES WILL BE DIFFERENT, MEANSFOR COMPARING THE AMPLITUDE OF SAID FIRST AND SECOND PULSES ANDINDICATING WHEN THE DIFFERENCE EXCEEDS A PREDETERMINED VALUE, MEANS FORINDICATING THE DIFFERENCE IN TIME BETWEEN THE TWO PULSES TO INDICATE THESPEED OF THE BATTER''S SWING, MEANS RESPONSIVE TO THE IMPACT OF THE BATWITH A BALL TO CREATE A THIRD PULSE OF ELECTRICAL ENERGY, AND MEANS FORINDICATING THE DIFFERENCE IN TIME BETWEEN THE THIRD PULSE AND ONE OF THEFIRST TWO NAMED PULSES.